1. Field of the Invention
The present invention relates to a lens shutter mechanism.
2. Description of the Related Art
In a known lens shutter type camera, a shutter and a diaphragm separate therefrom are juxtaposed in the optical axial direction. The shutter and the diaphragm each include a plurality of sectors (light intercepting members). Each sector is rotatably supported by a support shaft extending parallel with the optical axis. In an arrangement in which the shutter sectors and the diaphragm sectors are separately provided, the number of the support shafts about which the shutter sectors and the diaphragm sectors are rotated is increased, thus resulting in the restriction of freedom of design to prevent interference of the sectors with the support shafts. Specifically, if the shutter sectors and the diaphragm sectors are provided separately, it is difficult to further miniaturize a lens mechanism, which includes the shutter sectors and the diaphragm sectors, in the radial direction.
The present invention provides a lens shutter mechanism having a small outer diameter relative to the aperture size of the shutter or the diaphragm.
For example, in an embodiment, a lens shutter mechanism is provided, including a support frame having a photographing aperture; at least three shutter sectors which open and close the photographing aperture via rotating axes which extend parallel to the optical axis; and at least three diaphragm sectors which vary an aperture diameter formed by the diaphragm sectors to restrict the diameter of the photographing aperture, independently from the shutter sectors, via rotating axes which extend parallel to the optical axis. The support frame is provided with rotational center portions spaced from each other at equi-angular intervals about the optical axis, the number of the rotational center portions being same as each of the number of the shutter sectors and the number of the diaphragm sectors. Each of the rotational center portions rotatably and coaxially supports one of the shutter sectors and one of the diaphragm sectors.
The rotational center portions provided on the support frame can include support pivots extending in parallel with the optical axis, and the shutter sectors and the diaphragm sectors can be provided with support holes, in which the support pivots are rotatably fitted.
It is desirable for the lens shutter mechanism to further include a second support frame which is opposed to the support frame having the support pivots, in the optical axis direction, wherein the front ends of the support pivots engage with the second support frame. The shutter sectors and the diaphragm sectors can be provided between the support frames.
The lens shutter can further include shutter cam slots formed in the shutter sectors, respectively; a shutter drive ring having at least three follower projections which engage with the shutter cam slots, the shutter drive ring being rotated about the optical axis in forward and reverse directions to open and close the shutter sectors in accordance with profiles of the shutter cam slots; diaphragm cam slots formed in the diaphragm sectors, respectively; and a diaphragm drive ring having at least three follower projections which engage with the diaphragm cam slots, the diaphragm drive ring being rotated about the optical axis in forward and reverse directions to open and close the diaphragm sectors in accordance with profiles of the diaphragm cam slots. One of the shutter sectors and the diaphragm sectors are provided with through-holes through which the follower projections of one of the diaphragm drive ring and the shutter drive ring engage with the cam slots of the other of the shutter sectors and the diaphragm sectors to prevent interference of the one of the shutter sectors and the diaphragm sectors with the follower projections.
The through-holes can be respectively formed in the diaphragm sectors, so that the follower projections of the shutter drive ring extend through the through-holes.
It is desirable for the shutter cam slots of the shutter sectors to be located closer to the rotational center portions than the diaphragm cam slots of the diaphragm sectors, in the radial direction.
The lens shutter mechanism can further include a shutter drive motor which varies the angular displacement of the shutter drive ring in forward and reverse directions and varies the speed of the angular displacement thereof.
The lens shutter mechanism can be provided in a zoom lens barrel, wherein the diaphragm drive ring is rotated by a zooming operation of the zoom lens.
The present disclosure relates to subject matter contained in Japanese Patent Application No. 2001-81607 (filed on Mar. 21, 2001) which is expressly incorporated herein by reference in its entirety.